Stacking apparatus and method



June 29, 1965 E, A, HARTBAUER ETAL 3,191,927

STAGKING APPARATUS AND METHOD Filed June 20, 1965 4 Sheets-Shea?l 1 5% fuJn/air//Iwgg'gggle AMPIA/af i. TVI/Nin' BY Y iTTDf/YEK June 29 1965 E. A. HARTBAUER ETAL. 3,191,927A

STAGKING APPARATUS AND METHOD Filed June 2O 4 Sheets-Sheet 2 Mw/WWM 4 fraz/vifs June 29, 1965 E` A. HARTBAUER Erm. 3,191,927

STACKING APPARATUS AND METHOD Filed June 20. 1965 4 Sheets-Sheet 3 June 29, 1965 E. A. HARTBAUER ETAL 3,191,927

STACKING APPARATUS AND METHOD 4 Sheets-Sheet 4 Filed June 20, 1963 United States Patent O 3,191,927 S'IACKING APPARATUS AND METHOD Ellsworth A. Hartbauer, Concord, and Lawrence E.

Weinert, Antioch, Calif., assigner-s to Crown Zellerbach Corporation, San Francisco, Calif., a corporation of Nevada Filed June 20, 1963, Ser. No. 289,273 Claims. (Cl. 271-57) This invention relates generally to the stacking of generally at articles.

More particularly, this invention relates to an apparatus and method for forming generally flat and flexible articles, such as collapsed vbag tubes, into a series of successive stacks each of which is of predetermined height.

Still more particularly, this invention relates to an apparatus and method for feeding a stream of generally flat articles arranged in overlapped shingled fashion into a given location, at such location forming a plurality of 4such articles into a stack of predetermined height, and, when such stack has reached a predetermined height, positively interrupting flow of the succeeding articles in the stream while the previously formed stack of articles is removed from the stacking location. After such stack removal, flow of the stream of articles is reinstated until another stack of predetermined height is formed at said stacking location, following Which'liow of the stream is again temporarily halted while the other stack is removed from the stacking location. This sequence of operation is continued automatically and at a rapid rate until all articles fed from a source of supply in said stream have been formed into successive stacks or until the apparatus is'stopped for any given reason.

While this invention has particular utility when applied to the stacking of flexible, generally flat articles such as collapsed paper bag tubes, its utility extends to the stacking of other generally flat articles as well.

From the foregoing, it should be understood that objects of this invention include the following: the provision of apparatus for automatically stacking a stream of generally flat articles into successive stacks each of which is of predetermined height; the provision of a method for forming a stream of generally flat articles into successive stacks each of which is of predetermined height; the provision of an automatic article stacking apparatus which includes infeed conveyor means for feeding a stream of overlapped shingled articles to a stacking location, takeoff conveyors for` urging discrete articles in said stream to said stacking location, means for sensing when a stack Vof articles of predetermined height has been built up at said stacking location, means at said stacking location for supporting a plurality of articles one on the other While such articles are being formed into a stack, means for positively interrupting flow of the stream of articles to said stacking location while a previously formed stack of articles is being conveyed therefrom, and operating means and mechanism for actuating the various components of the apparatus in timed relationship with each other so that a high speed article stacking operation may be effected without halting article ow from a source of supply; and the provision of an article stacking apparatus in which certain operative components thereof are adjustable so that articles of varying sizes may be accommodated and stacks of Varying heights may be produced. These and other objects will become apparent from a study of the following disclosure in which reference is directed to u the attached drawings in which:

FIGURE l is a side elevational view of the subject apparatus; l

FIGURE 2 is a plan view of the subject apparatus;

FIGURE 3 is a partial vertical sectional view through the apparatus taken in the plane of line 3-3 of FIG. 2;

Patented June 29, 1965 ice FIGURE 6 is a partial vertical sectional View corre-v sponding in general respects to the showing of FIG. 3 which illustrates generally in schematic form part of the control means of the apparatus for actuating components thereof.

The apparatus illustrated is specifically designed to carry out its article stacking operation at high speeds upon a stream of articles fed from a source of supply of such articles. To this end, and in brief summary, the procedure of forming such articles into a plurality of successive stacks all of which are of predetermined height comprises conveying a continuous stream of articles from the source of supply with the articles arranged in partially overlapped shingled fashion. Hereinafter the articles to be stacked will be described as flexible generally fiat collapsed paper or like bag tubes but the invention is not limited to use in the stacking of bag tubes.

The bags to be stacked are arranged in overlapped shingled fashion as they are discharged from a tube forming machine which serves as a source of supply for the stream of bags to be stacked. The stream of overlapped bags is fed in a given direction to a stacking location and each bag in the stream is urged against a stop surface at said location so that individual bags are aligned -into a generally uniform stack at said location. The

number of bags fed to said location against the stop surface is sensed, in the illustrated embodiment, by measuring the height of the stack as it is being formed. When a bag stack of predetermined height has been fed against the stop surface, flow of additional bags in said stream to said location against said surface is positively but temporarily interrupted. l

During interruption of the iiow of the stream of bags against the stop surface, the previously formed stack is removed from the stacking location. After the stacking location has been cleared, flow of the stream of bags to the stacking location is again effected until another stack of bags of predetermined height is formed at said location, at which time ow of the bag stream is again ternporarily interrupted to permit removal of the second bag stack from said location. This procedure is repeated sequentially until the desired number of bags fed from a source of supply have been stacked. It should be understood that following removal of a bag stack from the stacking location, a subsequent operation normally is performed thereon, such as bundling, which forms no part of this invention.

The stacking procedure or method preferably is effected by a stacking apparatus of the type illustrated and described herein.

Referring to FIGURE l, a series or stream l of bags B, arranged in partially overlapped shingled fashion well known in the bag manufacturing art, is carried by any suitable conveyor means from a source of supply, such as a bag tube forming machine (not shown) into the bag stacking apparatus of this invention. In the illustrated embodiment the stream of bags is conveyed to the apparatus on an endless belt conveyor, generally designated 3, which comprises a series of laterally spaced endless belts 4 (FIGURE 2) which travel over pulley structure S mounted for rotation with a rotatable shaft 6 in the well known fashion. Any suitable means (not shown) may be employed for driving the conveyor 3 at a predetermined speed correlated with the speed of operation of the stacking apparatus. A l v The stacking apparatus proper comprises a suitable metal framework 7 by which the various components of the apparatus are supported. As seen in FIGURES 2 and 4, the `framework of the apparatus comprises opposite upright side frame members 8 and 9 between which the apparatus components are located.

Means for conveying or removing stacks of bags from the apparatus comprises a take-off conveyor generally designated 11 which extends beneath a bag stacking location 12, as perhaps best seen in FIGURE 1. The takeoff conveyor comprises a series of laterally spaced endless belts 13 (see FIGURES 2 and 4) which pass over a series of spaced pulleys 14 mounted on a rotatable shaft 16 at one end of the take-off conveyor and over a series of similarly spaced pulleys 17 mounted on a similarly rotatable shaft 18 at the opposite or discharge end of the take-off conveyor. Shafts 16 and 17 are journaled for rotation in suitable bearings supported on the apparatus side frame members.

As shown in FIGURES 2 and 4, shaft 16 has a drive sprocket 19 secured to one end thereof which is operatively connected to the power source of the apparatus in the manner to be described. Preferably during operation of the apparatus, the take-olf conveyor is continuously driven so that it is at all times ready to receive and carry away a stack of bags placed thereon. In this regard, it should be understood that the take-off conveyor belts are free of contact with the bags as they are being formed into a Stack on supporting means to be described.

In the embodiment illustrated, a series of freely rotating rollers 21 are spacedly positioned at the discharge end of the taire-off conveyor between extensions 22 and 23 of the side frame members of the apparatus framework to receive a stack of articles discharged thereto by the take-olf conveyor. The rollers 21 are provided to bridge a gap between the primary take-olf conveyor 11 and an auxiliary take-off conveyor 23 defined by a series of spaced endless belts 24 which pass over pulley structure 25 mounted on a shaft 26 rotated in any suitable fashion. Thus, carrying away of successive stacks of bags from said apparatus may be effected automatically by employing the auxiliary conveyor 23, or manually if such an auxiliary conveyor is not provided.

As seen in FIGURES 2 and 3, a supporting plate 31 is interposed between the upper and lower reaches of the belts 13 of the primary take-olf conveyor 11 and the upper reaches of such belts slide over the supporting plate during movement thereof. The supporting plate 31 adjacent the discharge end of the take-olf conveyor is generally continuous across the full width of the apparatus, but such plate has a series of spaced, linger-like projections 32 which underlie the upper reaches of the belts 13 adjacent the lopposite end of the take-off conveyor. These fingerlike extensions 32 permit movement of portions of bag supporting means vertically between the belts when a stack of bags is being placed on the belts in the manner to be described. Transverse bars 33 support plate 31 between the side frame members of the apparatus.

Interposed between the infeed conveyor 3 and the takeoif conveyor 11 is means generally designated 35 for urging individual bags being stacked into the stacking location against the stop Surface provided therein. Such urging means comprises movable mechanism in the form of a continuously rotating roller structure defined by a series of laterally spaced rollers 36 each of which is iixedly mounted for rotation with a rotatable shaft 37 journalled for rotation in suitable bearings provided on the side frame members of the apparatus framework. A planar supporting plate 38 is positioned between the infeed conveyor and the rollers 36 to support the bag stream therebetween if required. Shaft 37 of the roller structure is provided on one end thereof, as seen in FIGURES 2 and 4, with a drive sprocket 39 which is operatively connected with the afore-mentioned power source of the apparatus in the manner to be described so that rotation of the rollers 36 may be effected during operation of the apparatus.

As seen inrphantom lines in FIGURE 3, each of the bags fed into the apparatus passes over and the trailing end thereof is directly engaged under normal conditions with the rollers 36 of the roller structure. Because the roller structure is rotated counterclockwise as viewed in FIG. 3, each bag is positively urged by the roller structure int-o the 'stacking location againsta stop surface provided therein as seen in FIGURE 1.

This roller structure is an important feature of this invention in that it insures positive feeding of each bag against the stop surface. Because'bags frequently are quite ilexible, such positive feeding counteracts any tendency of the bags to bunch up or fold before they are properly positioned in stacked relationship within the stacking location.

A power source is provided for continuously driving the take-olf conveyor and the roller structure during apparatus operation. In the embodiment illustrated the power source comprises an electric motor 41 mounted on a suitable platform 42 extending beneath the take-olf conveyor. A belt 43 is secured to a pulley 44 mounted on the motor drive shaft and belt 43 passes over another pulley do (FIGURE 4) which is mounted on another rotatable shaft (no't shown) operatively connected with an adjustable speedl gear reduction unit 47. The unit 47 has a shaft 48 projecting therefrom on which a drive pulley 49 is mounted.

It is around the drive sprocket 49'that a suitable drive chain or belt 51 (seeFIGURE 1) passes. This drive chain or belt 51 also passes over the aforementioned sprockets 19 and 39 of the take-off conveyor 11 and roller structure 35. Thus the take-off conveyor and roller structure are driven by the same power source. In the embodiment illustrated an idler sprocket 52 (FIGURES 1 and 4) also is interposed between the sprockets 19 and 39 for the usual purpose. Upon actuation of the electric motor by any suitable electrical source, the take-off conveyor and roller structure may be driven at any suitable speed through the adjustable gear reduction unit 47. Movement of the take-olf conveyor and the roller structure is correlated with the speed of travel of the bag stream fed into the apparatus by the infeed conveyor.

'Bags to be stacked are urged by the roller structure against a stop surface which in the illustrated embodiment is provided with yielding characteristics as will be described. The stop surface is defined by releasable stop means generally designated 56 which comprises an elongated stop plate 57 normally positioned at the bag stacking location in the path of ytravel of the respective bags urged towards the discharge end of the apparatus by the roller structure. Stop plate S7 is pivotally supported for retraction out of the path of the bags to be stacked so that a bag stack formed against the stop plate may be removed from the apparatus by the take-off conveyor when the stack has reached a predetermined height.

As seen in FIGURES 2, 4 and 5, stop plate 57 is generally Lshaped in horizontal cross section and is secured by bolts 5S to a vertical mounting brace 59, which in turn is pivotallyV connected by means of pivot pin 61 to one end of a generally triangular horizontal mounting bracket 62. Bracket 62 in turn is lixedly secured to an elongated shaft 63 which projects laterally from the apparatus framework above the take-olf conveyor. Brace 59 is provided at its upper end with an anchor pin 64 by means of which a coil spring 66 is secured between brace 59 and the other end 67 of the bracket 62. Thus, spring 65 urges the brace 59 into contact with the rod 63 as seen in FIGURE 5 so that the stop plate 57 is maintained generally vertical.

However, pivotal movement of the stop plate in a clockwise direction as viewed in FIGURE 5 about the axis of pivot pin 61 against the urging of spring 66 is 5 permitted if a bag strikes the stop plate with a greater than normal amount of force, such as, for example, when the first bag of a stack is urged against the stop plate when frictional forces on the bag are relatively low due to its contact with the supporting means to be described.

The pivotal mounting for the stop plate precludes damage to bags fed thereto in that the plate may pivot an amount suiicient to preclude permanent bag damage. However, after the stop plate has pivoted to take up the shock and the bag has come to rest, the spring 66 urges the plate back to its normal generally upright position so that a generally uniform stack of bags may be formed against the planar surface thereof. Despite the fact that the stop plate can pivot as described, under all normal conditions the stop plate provides a generally rigid surface against which bags being stacked may be alined.

The end of mounting rod 63 remote from stop plate 57 is secured in a mounting block 71 which is slidably received upon a non-circular elongated pivot shaft 72 as seen in FIGURE 1. Shaft 72 extends longitudinally of the stacking apparatus and opposite ends thereof are journalled by suitable bearings (not shown) in mounting brackets '73 and 74 secured to a side frame member 8 of the apparatus adjacent the upper end thereof. Means to be described is provided for actuating and rotating pivot shaft 72 in a manner to be described to edect upward pivotal movement of the stop plate 57 periodically as required during a stacking operation.

Block 71 from which the stop plate supporting rod 63 projects is slidably movable along the length of shaft 72. So that the stop plate may be positioned at a predetermined location determined by the size of the bags to be stacked, a handle member 75 which has a threaded pin (FIGURE 4) threadedly engaged in block 71 is provided. Pin 76 extends through the block 71 into engagement with the shaft 72. Upon tightening of the handle 75, the pin 76 is urged against the shaft 72. Thus, the block 71, the supporting rod 63, and the stop plate 57 supported thereby, may be slid along shaft 72 and immovably positioned in a predetermined location of adjustment as required. The means for pivotally actuating shaft 72 to periodically raise the stop plate out of the path of a stack'of bags will be discussed hereina ter.

As mentioned previously, movable means is provided in the apparatus for supporting a plurality of bags above the take-oir` conveyor while such bags are being formed one on top of the other into a compact stack. Such supporting means normally is positioned above the level of the upper reaches of the belts 13 of the take-olf conveyor (see FIGURES 1 and 3) so that bags being stacked are held out of contact with thetake-oif conveyor.

When -a bag stack of predetermined height has been completed, the supporting means is moved generally downwardly to alocation below the level of the upper reaches of the take-off conveyor belts 13 so that the stack of bags is pla-ced onto the take-off conveyor for removal from the apparatus. In this regard, the supporting means includes mechanism for urging the bag stack in the same direction of movement of the take-olf conveyor so that the bag stack has impetus when it contacts the conveyor belts. Thus, the stack is not moved from a dead stop position by the take-off conveyor which would tend to misalign or topple the bags in the stack. By thus imparting initial movement to a bag stack as the Same is being transferred by the supporting means onto the take-offconveyon smooth conveying of the bags from the lstacking location is insured.

In the illustrated embodiment, the stack supporting means comprises a plurality of laterally spaced elongated supporting rods S1 interposed between adjacent belts of the take-off conveyor as seen in FIGURE 2. Normally the bag supporting rods 81 are positioned above the takeotf conveyor belts While bags are being stacked against the stop plate 57 as seen in FIGURES 1 and 3. Projecting upwardly from the end of each of the supporting rods 81 92 projects. Inside the cylinder 91, yone end of the pistonV adjacent the roller structure 35 is a narrow pusher plate 82. These spaced pusher plates cooperate to form a pushing surface which urges a stack of bags in the direction in which the take-0E conveyor moves when the supporting rods 81 are lowered, as viewed generally in FIGURES 3 and 6.

The supporting rods I81 are mounted for movement between their' raised and lowered positions in unison by means of transverse mounting brackets S3 and yS4 which extend transversely of the apparatus. Therespective supporting rods are secured to the transverse brackets in any suitable manner, such as by welding or bolting. Pivotally connected to the brackets S3 and S4 adjacent each side of the apparatus are pairs of vertical actuating links S6 and 87 which form part of the mechanism for actuating and moving the supporting rods between their raised and lowered positions. One pair of such actuating Ilinks are provided at each side of the apparatus with a link 86 of each such pair pivotally connected with an end of the transverse bracket 83, While the yother link 87 of each pair is pivotaly connected with an end of the other transverse bracket 84.

Adjacent their lower ends, the links 86 are supported by and j-ournalled on a pivot shaft 88 which extends between and is pivotally secured in suitable bearings ymounted on the opposite side frame members of the apparatus. The other pair of links 87 are similarly supported by and mounted on a pivot shaft S9 which also is journalled for rotation between the opposite side frame members of the apparatus. The shafts 88 and 89 thus form rotatable axes about which the supporting rods 81 may move as aV unit when it is desired to move lthe supporting rods between their raised and lowered positions. t

Thus, if the-links 87 are urged to the left as viewed in FIGURES 3 and 6, the supporting rods 81 and any bags stacked thereon are moved simultaneously to the left and downwardly about the axes of shafts 88 and 89 so that lthe supportingrods pass between the conveyor belts 13 to a level beneath the upper reaches of the conveyor belts.

During such motion, the pusher plates 82 ofthe supporting rods engage the trailing edges of the stacked bags and accelerate the bags longitudinally in the take-off conveying direction. After the bag stack has cleared the ends of the supporting rods, the rods are raised to support other bags being stacked.

-Mean-s for actuating the stack supporting rods 81 through the links 86 and 87 may take va-rious forms. In the embodiment illustrated, uid actuating means is provided, as seen in FIGURES 3 and 6, which takes the -form of pneumatic or hydraulic mechanism which includes an enclosed cylinder 91 from one end of which a piston rod rod 92 is connected with a uid actuated piston (not shown). Upon actuation of the piston by introducing a pneumatic or hydraulic fluid against one side of the piston,

- the piston rod 92 may be extended or retracted in the well known manner.

At its other end, the pist-on rod 92 is pivotally connected by means of a clevis 93 and pivot pin 94 intermediate the upper and lower ends of one of the supporting rod actuating links 87. Thus, comparing FIGURES 3 and 6, upon extension of piston rod 92 to the left, the bag supporting rods 81 will be moved to the left and downwardly a predetermined amount suicient to place a stack of bags on the take-oit conveyor. UponV retraction of the piston rod 92 into the cylinder 91 after a stack of bags has cleared the supporting rods, the supportingy rods will be moved to the right and upwardly to their normal position above the belts of the take-off conveyor.

Control means for regulating actuation of the control cylinder 91 yof the bag supporting means in timed relationship with the other operations of the apparatus will be described hereinafter,

Afurther important feature of this invention resides in the provision of means in conjunction with the aforementioned roller structure 35 to positively interrupt ow of the bag stream 1 into the stacking location while a previously formed stack of bags is clearing such location. Such ow interrupting means in the illustrated embodiment comprises a series of lateraly -spaced lift members 96'which project upwardly between the rolle-rs 36 of the roller structure 3S. At its upper end, each of the spaced lift members 96 is provided lwith a bag engaging insert 97, secured by welding or bolting or the like, to the lift members.

The lift members are normally retracted and retained below the upper level of the rollers 36 out of contact with the stream of bags passing over the rollers. However, the lift members are projectable so that their inserts 97 `are engageable with the undersu-rface of a predetermined one of the bags in the bag stream as seen in FIGURE 6 to thereby physically raise the bag stream off the roller structure to thereby positively preclude further feeding of the bag stream into the stacking location toward the stop plate 57. It is during such interruption of the bag stream that the supporting rods 81 are actuated and a previously formed stack of bags of predetermined height is placed `onto the take-oilc conveyor for removal from the apparatus.

At their lower ends, each of the lift members 96 is secured in any suitable manner, such as by bolting or welding, to a transverse supporting brace structure 98 which is movable generally vertically between the side frame members of the apparatus framework. The means for actuating the lift members in the embodiment illustrated is a suitable pneumatic or hydraulic cylinder 99 from one end of which a piston rod 101 projects. The upper end of this piston rod is connected by a clevis 102 and pivot pin 103 to the brace structure 9S from which the lift members project upwardly. The other end ofthe pis- -ton rod is attached to a piston (not shown) within cylinder 99 so that extension of retraction of the piston rod may be effected in the well known manner by introducing a'pneumatic or hydraulic fluid against one side of the piston. Upon extension of piston rod 101, the lift members are projected into contact with the undersurface of the bag stream, while retraction of the lift members is effected upon retraction of the piston rod.

The control means for regulating actuation of the piston rod 101 through cylinder 99 also will be described hereinafter but it should be understood that actuation of the lift members 96 through the cylinder 99 is timed with actuation of the pivotal stop plate 57 and the aforementioned supporting means so that 4the stop plate and supporting means are actuated promptly upon interruption of the flow of the bag stream into 4the stacking location.

An important auxiliary feature of this invention resides in the provision of auxiliary stop means 105 which is normally retracted out of the path of travel of bags to be stacked but which is periodically projectable at least partially into the path of movement of the bag stream to assist the aforementioned lift members 96 in positively interrupting liow of the bag stream while a previously formed stack of bags is being removed from the apparatus. Such auxiliary stop means comprises an auxiliary stop plate 106 which depends from a laterally extending mounting rod 107 as seen in FIGURE 4. Stop plate 106 may be secured to the rod in any suitable fashion and if desired, the same type of mounting arrangements described previously with respect to the primary stop pla-te 57 may be employed therewith.

Adjacent the side frame member 8 of the apparatus, the mounting rod 107 is movably secured by a slidable block 103 on a non-circular support shaft 109 which extends longitudinally of the apparatus. Shaft 109 is journalled at opposite longitudinal ends of the apparatus by bearing structures 110 and 111 secured to the framework of the apparatus as seen in FIGURE 1. To permit the auxiliary stop plate to be adjustably located and secured at a predetermined location along pivotal shaft 109, a

8 screw handle 111 having a threaded pin 112 (FIGURE 4) which threadedly extends through block 108 into engagement with shaft 109 is provided.

Through an actuating arrangement to be described, the shaft 109 is normally pivoted a partial turn in a counterclockwise direction as viewed in FIGURE 4 so that the auxiliary stop plate 106 is normally held in an upper position out of the path of movement of the bag stream. However, upon interuption of the flow of the bag stream by the lift members 96 and accompanying pivotal movement upwardly of the primary stop plate 57 to permit release of a bag stack to the take-oit conveyor, the auxiliary stop plate 106 is pivotally lowered into the path of the bag stream as viewed in FIGURE 6.

Thus, although flow of the bag stream is positively interrupted by the lift members engaging one of the underlying bags of the stream as seen in FIGURE 6, any tendency of the overlying bags of the stream to continue movement to the stacking location is precluded by such bags striking the lowered auxiliary stop plate 106. That is, such overlying bags merely pile up against the auxiliary stop plate 106 and form a partial stack thereagainst. Upon subsequent release of the bag stream to the stacking location by retraction of the lift members, the auxiliary stop plate 106 is automatically raised to its upper position as the primary stop plate 57 is returned to its lower position in the path of the bag stream.

Linkage means is provided to correlate raising of the primary stop plate 57 with raising of the lift members 96 and lowering of the auxiliary stop plate 106. As seen in FIGURES 1 and 4, such linkage means comprises a iirst generally upright actuating link 114 secured by a pivotal connection 115 at its lower end to the brace vstructure 98 which is actuated by the cylinder 99 to raise the lift members 96. As best seen in FIGURE 6, stabilizing links 116 project generally longitudinally adjacent tlie side frame members of the apparatus. The stabilizing links are secured adjacent one of their ends in any suitable manner to the brace structure 98 and thereby to the upwardly extending actuating link 114. At their opposite ends, the stabilizing links 116 are pivotally connected for rotation about the axis of a transversely extending shaft 117 which extends between the side frame members and is journalled therein. Thus, comparing FIGURES 3 and 6, upon actuation of the cylinder 99 to project the pistonl rod 101 to extend the lift members 96, the stabilizing links 116 are pivoted upwardly in conjunction with upward movement of actuating link 114.

At its upper end, actuating link 114 has pivotally connected therewith a connecting link 118 which is nonrotatably secured in any suitable manner to the aforementioned longitudinal pivot shaft 72 which actuates the primary stop plate 57. Thus, upon upward movement of link 114, the shaft 72 is pivoted counterclockwise as viewed in FIGURE 4 to pivot-ally raise mounting rod 63 and stop member 57 therewith, while downward movement of link 114 results in clockwise rotation of shaft 72 and corresponding downward movement of the stop plate 57.

To effect corresponding correlated pivotal movement of the auxiliary stop plate 106 with primary stop plate 57, the linkage means also includes an extension 119 which is immovably secured to and forms a bell crank with link 11S as seen in FIGURE 4. Link 119 of this bell crank isgcut out adjacent its upper end 120 and a projecting pin 121 secured to the lower end of a third link 122 is slidably engaged therewith in the cut out portion. Link 122 in turn is non-rotatably connected with the end of longitudinal pivot shaft 109, movement of which etects pivotal movement of the auxiliary stop plate 106 as described previously.

Thus, as actuating link 114 is raised by cylinder 99 to thereby pivot the bell crank defined by links 118 and 119 in a counterclockwise direction in FIGURE 4, the auxiliary stop plate is free to pivot downwardly with shaft 133 under the effects of gravity as the link 119 is moved to the left, thereby permitting pin 121 to move therewith. Conversely, however, when the actuating link 114 is drawn downwardly in FIGURE 4, the bell crank defined by links 118 and 119 is pivoted clockwise to thereby urge the pin 121 and its attached link 122 to the right in a counterclockwise direction to thereby physically raise the auxiliary stop plate 1116.

Link 122 has an extension 123 secured thereto for movement therewith which strikes a stop bar 124 as the stop plate 106 swings downwardly to limit such downward movement as required. Similarly, the upper end of link 119 strikes an adjustable stop 125 to limit downward movement of primary stop plate 57.

From the foregoing it should be understood-that the sequence of operation of this apparatus is as follow-s:

When a stack of bags of predetermined height has been urged against the primary stop plate 57, the stack height is automatically sensed and the lift members 96 are raised to halt the ilowof the bag stream against the stop plate. When the lift members have thus raised the bag stream from engagement with the rollers 36 of the roller stiucture 35, the primary stop plate 57 is pivoted upwardly and the bag supporting rods 81 are moved gen- Astream to assist further in positively halting flow thereof.

After a bag stack has cleared the stop plate 57, the components are returned to their normal position and thel sequence is repeated.

Control means are provided to correlate the aforementioned activities of the apparatus components through the actuating cylinders 91 and 99. ln this regard, means is provided for sensing when a stack of bags of predetermined height has been fed to the stacking location and urged against the primary stop plate 57 so that removal of such bag stack from theapparatus is in order. Such sensing means in the illustrated embodiment includes electrical switch mechanism engageable by the bags being stacked which includes a switch arm'131 positioned to depend in the path of bags fed against the primary stop plate 57. As seen in FIGURES 1 and 5, switch arm 131 is provided with a generally right angled 'bent lower end elbow portion 132.

Switch arm 131 is pivotallyconnected with and depends from an electrical switch 133. Switch 133 in turn is adjustably mounted for vertical movement on a supporting bracket 134 (FIGURE 5) which dependsfrom a mounting rod 135 which extends laterally of the apparatus above the take-cfr" conveyor. Rod 135 in turn is slidably connected via .a slidable block 136 and threaded handle 137 to an elongated `shaft 13S which extends longitudinally of the apparatus as seen in FIGURE 1. Thus, arm 131 or" the switch 133 may be positioned selectively in accordance with the size of bags being stacked. When switch arm is pivoted to the `left from its position shown in FIGURES land 5, the normally open circuit of the switch 133 is closed to transmit a control signal to actuate cylinder 99 as will be described.

The bend in the lower end of the switch arm is arranged so that a bag stack of certain height may come into contact with the stop plate 57 without any bags thereof contacting the switch or effective pivotal movement thereof to a degree sufficient to close the electrical circuit controlled by switch 133. However, as the height of the bag stack reaches a predetermined level, depending upon the location of the bent elbow in the switch relative to the bag supporting rods 81, that bag of the stack which results in the stack reaching a predetermined height will strike the bent elbow portion of the switch arm and thus will effect pivotal movement of the switch arm and closing of the electrical circuit governed by switch 133.

So that the height of the stacks of bags which maybe formed in the apparatus may be varied, switch 133 is vertically adjustable to permit raising or lowering the position of the bent elbow portion of switch arm 131 relative to the supporting rods 31. 1n the illustrated embodiment, a threaded rod 139 (FIGURE 5) is secured at one end to switch 133 and extends through :an angled extension 140 in bracket 134 which slidably guides the switch. A threaded adjusting nut member 141 is threaded on the upper end of rod 139 and engages the bracket extension 140. By changing the position of nut 141 on rod 139, the lswitch and switch arm may be adjustably raised or lowered.

Referring now to the schematic showing of FIGURE rupt How thereof and to actuate the linkage describedv previously which raises, the primary stop plate 57 and lowers the auxiliary stop plate 106.

The control means of the apparatus also includes an electrical arrangement by means of which the bag supporting rods are actuated to lower a stack of bags of predetermined height onto the take-oilc conveyor when switch 133 effects stoppage lof flow of the bag stream. A second electrical switch 151 is mounted on the side frame member 8 of the apparatus in line with the actuating link 114 als best seen in FIGURE 4. Thus, when the actuating link moves upwardly in-conjunction with raising of lift members 96, `it strikes a switch arm 152 projecting from switch 151 to thereby close a normally open circuit between switch 151 anda second solenoid valve 153 (see FIGURE 6). As the circuit is closed, solenoid valve 153 acts in a known manner on a fluid source to effect introduction of actuating fluid through a valve 155 into contact with the piston in cylinder 91. This extends piston nod 92. Thus, as the circuit between switch 151 andsolenoid valve 153 is closed by actuation of the switch arm 152, the piston rod 92 is extended to move the ysupporting rods to the left rand downwardly as viewed in FIGURE 6 to release a stack of bags tonto the takeoff conveyor.

While the stack of bags is moving from the apparatus on the take-ott conveyor, switch arm 131 of the first mentioned switch 133 rides over the top of the bag stack as seenV in FIGURE 6, thereby maintaining the circuit to solenoid valve closed so that lift members 96 are extended and stop plate 57 is retracted. However, when the bag stack is moved clear of the stop plate 57 by the take-off conveyor so that the switch arm 131 clears the bagr stack and is free to pivot downwardly to its normal position shown in FIGURE 1, the circuit to solenoid valve 1451s again opened. Solenoid valve 145 then acts upon the iluid source and, throughanother valve 156, effects introduction of fluid against the opposite side of the piston in cylinder 99 to effect withdrawal of the piston rod 161 and attendant retraction of the lift'members 96.

As lift members 96 are retracted, link 114 is also retracted so that the Vswitch arm 152 clears link 114 to thereby open the circuit between switch 151 and its associated -solenoid valve 153. As the circuit is thus opened, solenoid valve 153 acts upon iluid source and,

Vthroughanother valve 157, effects introduction of iluid against the opposite side of the piston in cylinder 91 to raise the supporting rods totheir bag supporting position above the belts of thetakeaoi conveyor. Timing of the .sequence of the operation regulated by the electrical control means is such so that the primary stop plate 57 is fully returned to its lower bag blocking position before subsequent bags from the bag stream `reach the stop plate.

The apparatus preferably is provided in its electrical circuit with a main on-o control -switch 161 (FIGURE 6). The necessary electrical control equipment is located in a control box 162 (FIGURE l) conveniently mounted adjacent the infeed end of the apparatus.

While specic details of actuation of the cylinders 91 and 99 through their respective tluid supply sources by the respective solenoid controlled valves have not been described, the operation of the cylinders via the electrically controlled solenoid valves is well known.

Actuation of the various components of the apparatus as described herein is eiected sequentially under the control effects of the electrical control arrangement described so that a series of successive stacks of bags of predetermined height is formed automatically so long as a stream of bags is fed into the apparatus.

From the foregoing, it should be understood that this invention relates to an automatic and high speed apparatus and methodl by which a continuous supply of exible, generally flat articles, such as collapsed paper bag tubes, may be fed to a stacking location and formed at such location into a series of successive bag stacks, each of which is of a predetermined height.

Having thus made a full disclosure of this invention, reference is directed to the appended claims for the scope to be atorded thereto.

We claim:

1. Article stacking apparatus comprising means for feeding a series of generally flat articles to be stacked from a source of supply, said feeding means including motion-imparting structurel for engagement with each such article to positively advance the same, releasable stop means against which successive articles are fed by said feed means, movable means for supporting a plurality of articles as such articles are formed into a stack against said stop means, take-off conveyor means for receiving and carrying away a stack of said articles when said supporting means is moved and when saidV stop means is released, height-measuring control means for sensing when a stack of articles of predetermined height has been formed against said stop means and for thereupon effecting release of said stop means and movement of said supporting means, such movement of said supporting means effecting placement of such stack of articles on said conveyor means for movement of said stack thereby from said apparatus, and means for displacing articles from said motion-imparting structure so as to positively interrupt feeding of successive articles toward said stop means while said supporting means is placing a previously formed stack of articles on said conveyor means.

2. Article stacking apparatus comprising means for feeding a series of generally fiat articles arranged in overlapping shingled fashion from a source of supply, said feeding means including motion-imparting structure for engagement with each such article to positively advance the same, stop means against which successive articles are fed by said feed means, means for supporting a plurality of said articles as such articles are being formed into a stack against said stop means, take-off conveyor means for receiving and carrying away a stack of said articles, height-measuring control means for Isensing when a stack of articles of predetermined height has been fed against said stop means and for thereupon effecting removal of such stack from said apparatus on said conveying means, and mechanism for interrupting ow of articles by raising said seriesof articles from said motion-imparting structure While a previously formed stack of articles is being moved from said apparatus by said take-off conveyor means.

3. Article stacking apparatus comprising infeed conveyor means for feeding a series of generally at overlapped articles to be stacked from a source of supply, releasable stop means against which successive articles to be stacked are fed, positively driven roller structure .f1.2 interposed between said infeed conveyor means and said stop means over which successive articles pass, said roller structure being operative to positively advance successive articles fed thereto by said infeed conveyor means Vagainst said stop means, movable means for supporting a plurality of said articles as such articles are formed into a stack against said stop means, take-off conveyor means for receiving and carrying away a stack of said articles when said supporting means is moved and when said stop means is released, control means for sensing when a stack of predetermined height has been formed against said stop means and for thereupon effecting release of said stop means and movement of said supporting means, such movement of said ysupporting means effecting placement of such stack on said take-olf conveyor means for movement of said stack thereby from said apparatus, said control means also sensing when such stack is carried by said take-off conveyor means beyond said stop means and thereupon returning said stop means to its operative posi- Vtion to receive thereagainst -successive articles to be stacked, and mechanism in conjunction with said roller structure for raising said series of articles off said roller structure to thereby interrupt flow of articles toward said stop means while said stop means is released.

4. In apparatus for stacking generally flat articles in successive stacks of predetermined height, means for feeding a succession of overlapped shingled articles in a predetermined direction including positively driven movable structure over which successive articles pass for positively urging such articles in said direction, projectable and retractable mechanism in conjunction with said movable structure for positively displacing articles therefrom to interrupt passage of articles in said direction, and control means engaged by articles passed over said movable structure for actuating said mechanism when a stack of articles of predetermined height has been formed to thereby interrupt llow of successive articles while said stack of articles is removed from said apparatus.

5. In apparatus for stacking generally flat articles in successive stacks of predetermined height, means for feeding a stream of articles arranged in overlapped shingled fashion in a predetermined direction, said feed means including positively driven roller structure over which said article stream passes for urging individual articles in said direction, projectable and retractable mechanism in conjunction with said roller structure for positively displacing articles therefrom to interrupt passage of successive articles over said roller structure to thereby temporarily halt ow of said article stream, said mechanism including lift members normally retracted beneath the level of said roller structure out of engagement with said stream of articles, said lift members being periodically projectable above said roller structure into engagement with an article of said stream of articles to lift the same from said roller structure, and control means engaged by articles fed by said roller structure for sensing when a stack of such articles of predetermined height has been formed and to thereupon actuate said mechanism to project said lift members into contact with said stream of articles to thereby interrupt flow of said stream so that said stack of articles may be removed from said apparatus, and to thereafter actuate said mechanism to retract said lift mernbers to permit feeding of subsequent articles of said stream in said direction by said roller structure.

6. The combination of claim 5 which includes auxiliary stop means normally retracted out of engagement with said stream of articles and periodically projectable into contact with said stream of articles to at least partially block and thereby assist said lift members in interrupting ow of said stream While said lift members hold said stream out of contact with said roller structure, said auxiliary stop means being actuated in conjunction with actuation of said lift members.

7. Article stacking apparatus comprising releasable stop means against which a stream of overlapped generally flat articles, such as bag tubes, to be stacked are fed in sequence, a take-off conveyor adjacent said stop means for receiving and carrying away from said stop means a stack of said articles when said stop means is released, roller structure over which said articles pass for urging successive articles against said stop means, movable means for supporting a plurality of said articles above said take-olf conveyor as such articles are being formed into a stack of predetermined height against said stop means, lift members in conjunction with said roller structure and projectable thereabove when actuated to raise said stream of articles otl said roller structure to thereby interrupt flow of such articles against said stop means, fluid means for actuating said lift members to project and withdraw the same relative to said roller structure, other fluid means to actuate said stop means and said supporting means to permit placing of a stack of articles on said take-off conveyor, electrical control means to sense when a stack of articles of predetermined height has been formed against said stop means and to thereupon transmit a control signal to said lift member, iluid means to actuate such iiuid means to elect projection of said lift members into contact with said stream of articles to raise said articles from said roller structure thereby to interrupt flow of said articles, said control means also being adapted to transmit a signal to said last mentioned fluid means to eiect release of said stop means and movement of said supporting means to place a stack of articles on said take-off conveyor when flow of said article stream is interrupted by said lift members.

8. The combination of claim 7 which includes auxiliary stop means normally retracted out of engagement with said stream of articles and periodically projectable into contact with said stream of articles to at least partially block and thereby assist said lift members in interrupting ilow of said stream while said lift members hold said stream out of contact with said roller structure, said auX- iliary stop means being actuated in conjunction with actuation of said lift members.

9. Apparatus for stacking generally ilat articles such as collapsed bag tubes in successive stacks which are of generally equal height, comprising an infeed conveyor for feeding a stream of articles arranged in overlapped shingled fashion into said apparatus, a take-oit conveyor for removing successive stacks of articles from said apparatus, movable supporting means normally positioned above said conveyor for supporting a plurality of articles While the same are being stacked, pivotal stop means adjacent said supporting means and normally positioned in the path of articles fed onto said supporting means, means for actuating said stop means and said supporting means to pivot said stop means upwardly and to move said supporting means generally downwardly when a stack of articles of predetermined height has been fed against said stop means, roller structure between said infeed conveyor and said take-off conveyor over which said stream of articles passes, said roller structure urging individual articles in sequence onto said supporting means and against said stop means, projectable and retractable lift members in conjunction with said roller structure normally retracted below the level of said roller structure, means for actuating said lift members to move the same upwardly above the level of said roller structure into engagement with said stream of articles to raise said stream oil said roller structure to thereby interrupt flow of articles onto said supporting means, and control means for sensing when a stack of articles of predetermined height has been fed against said stop means and for thereupon effecting actuation of said lift members by their associated actuating means to interrupt flow of said article stream and to thereafter eltect raising of said stop means and lowering of said supporting means by their associated actuating means to effect placement of such stack of articles onto said take-01T conveyor and removal of such stack from said apparatus by said take-oil conveyor, said control means also sensing when such stack has cleared said stop means on said take-off conveyor so that said stop means, said supporting means and said lift members may be returned by their associated actuating means to their normal positions to permit formation of another stack on said supporting means.

10. The apparatus of claim 9 which includes auxiliary stop means pivotally mounted above said stream of articles passing over said roller structure and normally retracted out of contact therewith, and means for actuating said auxiliary stop means to pivot the same downwardly into the path of movement of said stream of articles as said lift members are raised to interrupt ilow of said stream over said roller structure, said auxiliary stop means when pivoted downwardly at least partially blocking the path of said stream of articles and providing a stop surface against which a partial stack of articles may form while a previously formed stack is being removed from said apparatus by said take-off conveyor.

References Cited by the Examiner UNITED STATES PATENTS 2,228,887 1/41 Peterson 214-6 2,424,093 7/ 47 Harred 93--93 2,852,990 9/58 Roe 93-93.3

ROBERT B. REEVES, Acting Primary Examiner.

RAPHAEL M. LUPO, Examiner. 

1. ARTICLE STACKING APPARATUS COMPRISING MEANS FOR FEEDING A SERIES OF GENERALLY FLAT ARTICLES TO BE STACKED FROM A SOURCE OF SUPPLY, SAID FEEDING MEANS INCLUDING MOTION-IMPARTING STRUCTURE FOR ENGAGEMENT WITH EACH SUCH ARTICLE TO POSITIVELY ADVANCE THE SAME, RELEASABLE STOP MEANS AGAINST WHICH SUCCESSIVE ARTICLES ARE FED BY SAID FEED MEANS, MOVABLE MEANS FOR SUPPORTING A PLURALITY OF ARTICLES AS SUCH ARTICLES ARE FORMED INTO A STACK AGAINST SAID STOP MEANS, TAKE-OFF CONVEYOR MEANS FOR RECEIVING AND CARRYING AWAY A STACK OF SAID ARTICLES WHEN SAID SUPPORTING MEANS IS MOVED AND WHEN SAID STOP MEANS IS RELEASED, HEIGHT-MEASURING CONTROL MEANS FOR SENSING WHEN A STACK OF ARTICLES OF PREDETERMINED HEIGHT HAD BEEN FORMED AGAINST SAID STOP MEANS AND FOR THEREUPON EFFECTING RELEASE OF SAID STOP MEANS AND MOVEMENT OF SAID SUPPORTING MEANS, SUCH MOVEMENT OF SAID SUPPORTING MEANS EFFECTING PLACEMENT OF SUCH STACK OF ARTICLES ON SAID CONVEYOR MEANS FOR MOVEMENT OF SAID STACK THEREBY FROM SAID APPARATUS, AND MEANS FOR DISPLACING ARTICLES FROM SAID MOTION-IMPARTING STRUCTURE SO AS TO POSITIVELY INTERRUPT FEEDING OF SUCCESSIVE ARTICLES TOWARD 